I just can't sustain my suspension of disbelief with Leliana as Divine.
If we'd gone a thousand years with no major magical catastrophe and people had started treating mages as 'no big deal' in spite of Chantry doctrine, then I could see a new message being accepted. Just look at various social issues the Church in real life has started taking a 'softer' stance on.
Thedas, however, has endured magical catastrophe after magical catastrophe, including a massive hole in reality that allowed demons to invade. Regardless of if mages assisted in resolving the issue, the fact remains that the problem was caused by a mage who was, in turn, supported by other mages.
Additionally, regardless of which side you choose, Templars or Mages, mages also unlawfully occupied a major defensive and trade hub of Ferelden, so I'm not seeing that nation being particularly welcoming of those with a magical talent any time soon, and other nations could easily take it as a warning of what could happen to them.
Then there's the matter of mages corrupting and nearly destroying two branches of an order the common man views as heroes. Assuming they survive whatever horror the epilogue implies, I can easily see the Grey Wardens taking a much harsher approach to magic in their ranks as well.
I mean, when you simply tally up the magical awful in the last decade, with a Blight, a rebellion, and the Breach crisis, assuming everyone will accept rainbows and nugs Leliana's reforms just doesn't work for me, and knives and threats Leliana really isn't much better.